<?php
$username = 'admin';
$password = 'letmein';

if (isset($_SERVER['PHP_AUTH_USER']) &&
	isset($_SERVER['PHP_AUTH_PW']))
{
	if ($_SERVER['PHP_AUTH_USER'] == $username &&
		$_SERVER['PHP_AUTH_PW']   == $password)
		echo "You are now logged in";
	else die("Invalid username / password combination");
}
else
{
	header('WWW-Authenticate: Basic realm="Restricted Section"');
	header('HTTP/1.0 401 Unauthorized');
	die ("Please enter your username and password");
}
?>